December weather forecast
Rowland Heights, CA

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Weather in December

December, the first month of the winter in Rowland Heights, is still a comfortable month, with an average temperature fluctuating between 49.5°F (9.7°C) and 64.9°F (18.3°C).

Temperature

December stands out as Rowland Heights's coldest month, with an average high-temperature of 64.9°F (18.3°C) and a low-temperature of 49.5°F (9.7°C).

Humidity

The average relative humidity in December in Rowland Heights is 51%.

Rainfall

The month with the most rainfall is December, when the rain falls for 6 days and typically aggregates up to 1.61" (41mm) of precipitation.

Daylight

The month with the shortest days is December, with an average of 9h and 54min of daylight.
On the first day of December, sunrise is at 6:39 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 4:53 pm PST.

Sunshine

The months with the least sunshine are February and December, with an average of 6.8h of sunshine.

UV index

January, February, November and December, with an average maximum UV index of 4, are months with the lowest UV index. A UV Index of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for average individuals.
Note: A maximum high daily UV index of 4 during December translates into the following directions:
Heed the precautions - It is counselled to guard against solar damage. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Updated: Aug 30, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest month?

With an average high-temperature of 64.9°F (18.3°C) and an average low-temperature of 49.5°F (9.7°C), December is the coldest month.

What are the temperatures in December?

The average high-temperature and low-temperature in Rowland Heights during December are 64.9°F (18.3°C) and 49.5°F (9.7°C) respectively. In September, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, is calculated to be 87.8°F (31°C).

What is the average humidity in December?

The average relative humidity in December is 51%.

What is the wettest month?

The month with the most rainfall is December, when the rain falls for 6 days and typically aggregates up to 1.61" (41mm) of precipitation.

How much does it rain in December?

In Rowland Heights, in December, it is raining for 6 days, with typically 1.61" (41mm) of accumulated precipitation.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 54min of daylight.

What is the average length of the day in December in Rowland Heights?

The average day length in December is 9h and 56min.

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 6:39 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 4:53 pm PST.

What is the month with the least sunshine in Rowland Heights?

The months with the least sunshine are February and December, with an average of 6.8h of sunshine.

How many hours of sunshine does Rowland Heights have in December?

In December, the average sunshine duration is 6.8h.

What are the months with the lowest UV index?

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 4.

How high is the UV index in December?

The average daily maximum UV index in December is 4. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Rowland Heights, CA

Average temperature in December - Rowland Heights, CA
  • Average high temperature in December: 64.9°F

The warmest month (with the highest average high temperature) is August (88.3°F).
The month with the lowest average high temperature is December (64.9°F).

  • Average low temperature in December: 49.5°F

The month with the highest average low temperature is August (66.2°F).
The coldest month (with the lowest average low temperature) is February (48.9°F).

Average pressure in December
Rowland Heights, CA

Average pressure in December - Rowland Heights, CA
  • Average pressure in December: 30.07"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

Average wind speed in December
Rowland Heights, CA

Average wind speed in December - Rowland Heights, CA
  • Average wind speed in December: 5.2mph

The windiest month (with the highest average wind speed) is April (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.6mph).

Average humidity in December
Rowland Heights, CA

Average humidity in December - Rowland Heights, CA
  • Average humidity in December: 51%

The month with the highest relative humidity is June (59%).
The month with the lowest relative humidity is November (46%).

Average rainfall in December
Rowland Heights, CA

Average rainfall in December - Rowland Heights, CA
  • Average rainfall in December: 1.61"

The wettest month (with the highest rainfall) is December (1.61").
The driest months (with the least rainfall) are June and August (0.04").

Average rainfall days in December
Rowland Heights, CA

Average rainfall days in December - Rowland Heights, CA
  • Average rainfall days in December: 6 days

The month with the highest number of rainy days is March (6.6 days).
The month with the least rainy days is June (1.1 days).

Average daylight in December /
Average sunshine in December
Rowland Heights, CA

Average daylight in December / Average sunshine in December - Rowland Heights, CA
  • Average daylight in December: 9h and 5min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in December: 6h and 5min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 48min).

Average sunshine days in December
Rowland Heights, CA

Average sunshine days in December - Rowland Heights, CA
  • Average sunshine days in December: 24 days

The month with the most sunshine days is August (28.2 days).
The month with the least sunshine days is February (21.6 days).

Average UV index in December
Rowland Heights, CA

Average UV index in December - Rowland Heights, CA
  • Average UV index in December: 4

The month with the highest UV index is August (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 4).

Average cloud cover in December
Rowland Heights, CA

Average cloud cover in December - Rowland Heights, CA
  • Average cloud cover in December: 22

The months with the most cloud cover are March and December (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 5).

Average visibility in December
Rowland Heights, CA

Average visibility in December - Rowland Heights, CA
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Rowland Heights, California, USA

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